Technical 235 backfiring and dying off

The condenser has been covered. Check connections also.
Here is something else to consider....
A failing fuel pump...
The fuel pumps on these commonly go out. If the pump is older or rebuilt from a older kit , the reformulated gasoline may have damaged the diaphragm. A working but failing fuel pump may explain the high speed loss of power and even the back fires from fuel starvation. Also a failing/leaking fuel pump could let gasoline into the crankcase.

 

I actually replaced the fuel pump about two months ago. I had the OG dual action pump die on me at an intersection again before this Chevy I’d never even pulled a spark plug or done a valve cover in my LIFE so needless to say she’s keeping me on my toes

 

A bad condenser CAN seem like a bad fuel pump. My experience with a bad condenser was it would run along fine down the road then all of a sudden it would act like someone pinched the fuel line off and it would die. But let it set for a bit and it would start and run for another mile then pow, same thing. It ended up being a bad condenser. If you suspect the condenser, when it acts up pull a plug wire or take the dist cap off and crank it, if the fire is nice and blue, the condenser is good. If it's pink, condenser is bad. You must have a strong bluish spark. A pink spark is not hot enough to fire the mixture. I believe the time I messed with it sitting turning the key off and on with the engine dead gave the bad condenser time to re-charge. Then it would run until the condenser gave up the ghost again. Pink spark, bad condenser. JMO. Lippy

 

lippy, this is very reminiscent of what was happening when it got bad. It rolled OK except for what felt like the motor working pretty hard to achieve the higher rpms. But when it did die on me, it fired right up after. It even died at a red light, and fired back up by the time the light turned green. So again all this feedback is making me feel much better. Now the hard part, finding the goddamn time to tinker with it

 

I'm not saying it IS a condenser but it could be. They will do some funny stuff. I would also check the wire from the negative side of the coil to the distributor to make sure it is not shorting or is grounding inside the distributor or against the dist housing intermittently. Hope you get it sorted out. Lippy

 

check this out, a little more random insight on everything. The day or two before all this happened I noticed my wire from the negative side of the coil to the dizzy was a bit loose. The threads on the bolt that holds the rubber block (heard it referred to as a power block/ground block) are a bit chowdered up, so I picked up a flat washer and a lock washer to bring the nut that hold the wire a few threads back to some healthier threads. Any possibly that could cause everything to ground out? Or perhaps roach the condenser?

 

Plumbing is easy!

Hot on the left, Cold on the right, shit down the middle, Payday is on Friday.

 

you’re forgetting never bite your finger nails

 

If you see a tach rpm slowly changing and the engine is dying, then you know the ignition is fine and something else is killing the engine. Unless it drops to zero and the rear wheels lock up then you know its a mechanical issue.
If you see the tach instantly drop to 0 and the engine dies as well then you have an ignition problem.
If you see the tach and the dash gauges/lights go out, then you have an electrical power problem.

The condenser acts as the shock absorber for the points, since the points arc everytime they open/close the condenser helps buffer that and reduce wear.
However, the points/condenser still need to have a resistor inline to operate correctly.
You do not want full battery voltage reaching the points, this will fry the points and condenser in short order.
Whenever you have points you use a ballast(resistor) 6V or 12V, if this isn't present then you will just continue to burn through points/condensers.

Need to install a 12V compatible ballast resistor and coil.

Ford did the resistor wire, GM did the ballast block.
Certain coils have their own built in resistor, but that is for the coil itself on electronic ignition systems.
With the Pertronix FlameThrower it has a built in resistor since the factory ballast resistor is removed when the points are removed, and the electronic pickup works best with 12V.

When reinstalling the points you need to reinstall the ballast resistor.
Points/condenser need a ballast resistor or they will burn up.
AC Delco Ballast resistor 12336832 and AC Delco coil 12337166 or equivalent.(anything off a 12V GM points vehicle from 55-73 would work for now).

If it's blown or open the points won't function correctly. It is the shock absorber for the points.
If you've ever ridden in a car with blown shocks, you know it rides like crap, same thing happens with the points electrically. They will just get hammered.
Points are a switch, it's what open/close and allows the coil to saturate.
Since the vehicle is a DC system the only way to create a magnetic field of the windings inside the coil is to turn the coil ON/OFF, that is what the points do.
When the points open/close a magnetic field is created. This magnetic field in the primary(low voltage) windings induces a voltage into the secondary(high voltage) windings. This is due to the difference in wire size/windings.
It's a ratio.
We can't increase wattage, but we can increase voltage while decreasing amperage, this is how we can get 30-45KVolts from a '12' volt system. It's also why you can get blasted with a spark from the ignition and it won't kill you(unless you have a pacemaker). There are no amps behind it. But 120V from your household socket does have amps so it will.

That is an insulating block and the wires/washer should not be grounding out to the distributor. If the wire harness is being strained or moves under acceleration it will ground out, it may not fully ground out but if it rubs it will sap power from the coil and you will have a secondary set of points that will cause misfiring as well as not allowing the coil to fully saturate when it is actual time to fire. Which will lead to a no or weak spark condition. It's like having a second set of uncontrolled points in series.

So two things to fix.
Install a ballast resistor inline with the coil.
Switched 12V power > ballast resistor > coil + >coil - >insulating block>points/condenser.

Fix/replace the insulating block on the distributor. If you can't fine one right away you can temporarily fix/improve it by wrapping it in some electrical tape to prevent unwanted shorts to ground.

I would also suggest taking several pictures of the ignition system, the wiring to the ignition system, and for S&G the wiring of the 12V conversion and post them in this thread.

If it is an 12V alternator conversion, the wiring from a generator to an alternator are quite different and use different voltage regulators. There may be a few other things that are not done entirely correct.

 

Mine did something. Fried points fast.
Changed the ballast resistor and points lived happily ever after.
Why?
Don’t know.
I’m not an electrician, I hit cars with hammers.

 

the insulator block isn’t the issue per say, it’s the bolt going through the block that has some shitty treads. Any idea where I can find a replacement for that? I’m able to find blocks on eBay, but none seem to come with the nuts and bolts as well. Do you think snugging up the nut as much as I can and wrapping the whole thing in electrical tape will work for the time being?

I’ll hopefully find some time in the next few days to find myself a ballast resistor, and hopefully get that in so I can then turn my attention towards going and points to hopefully get this all sorted out.

 

I see that you said you have aftermarket tach, I would unhook it. They can cause ign. troubles.

 

You can probably get the bolt and/or insulator from Philbin Electric. He carries a lot of distributor parts. http://www.philbingroup.com/

 

Reminds me of an off top car I had and it was the condenser.

 

Update: replaced the points today and it seem to drive much better without any of the hiccups and rough driving. I’ll give it a few weeks of driving (to be sure that was it) and then I think I’ll look into a ballast resistor. Those last points had maybe 1-2 miles on them. Not sure if that’s an average expectancy, but anything to keep the points from getting hammered sounds like a good idea to me

 

2 miles on a set of points? Maybe ya got the gap right this time

 

Usually find the minuscule stuff like that on farm/tractor sites.
Round shoulder.
https://www.stevenstractor.com/home...rminal-insulator-assembly-round-shoulder.html
Square shoulder.
https://www.stevenstractor.com/home/delco-distributor-terminal-insulator-square-shoulder.html
I think those are the bushings, but verify.
If you need another nut I *think* the threads were 10-24.

If the other set of points only lasted a couple days with no ballast, then the next set of points is probably not going to last much longer.
Points are not meant to take full battery/charging system voltage. Get a ballast.

 

This is your problem.

Ignition Switch Hot....ballast.....coil....Done!!!
https://www.summitracing.com/parts/sum-g5218
The box stores should have these too. For whatever reason, I have had better luck ordering for a Chrysler product. So if they have to have a year model and all that horseshit.....1965...1970 dodge truck, 318 blah blah blah.....

Get the connectors. Get a crimper, a real crimper. Get some shrink tube...
You can do it at the ignition hot wire under the dash.
You can do it at the ignition hot wire under the hood, say at the firewall.
Heck, you can even do it between the coil and the distributor. That's not the correct way! But I did that once back when I was a dumbass.

Do not worry about 12V to coil on ignition start and all that BS....just wire the ballast to ignition hot. It's a 15-30 minute job.

You have to have this!!!!
Sure. It will will run fine for a while without it until it does not, as you have experienced.

What happens is straight 12V fry the points. The points burn...carbon builds up on the contacts and they are done. They may last.....10 miles.....100 miles.......maybe more, maybe less.
With the ballast. they will last thousands of miles.

 

ive been having simular problems with mine . new coil . no fix . new fuel pump no change . thought id try a new condens

er .went to the parts store .$15.oo .for cheap chinese junk. never mind ! im waiting now for my new dist..no coil.no points .no well worn dist .new plug wires new advance .we'll see !! should arrive today

 

Gosh, I wonder ... where that spiffy new distributor was manufactured?

 

He needs a ballast.

Without a Ballast Resistor to protect the points, it make no difference how good the condenser is.

 

i dont care if its made in antartica if it works ! but ill know today. if that dont fix it im driving it off a cliff . the ultimate cliff hanger . if you dont hear from me ........!

 

I have officially learned this the hard way, just like anything else in my life! Ballast resistor is coming soon. I was going to mount it to the firewall, and run the hot wire going to the positive side of the coil coming off the started to the resistor, and then a run from the resistor to the positive side of the coil, and be done with

 

Side question though regarding points gap. I’ve always done feeler gauge at .019” as the shop manual says. Tighten up my set screw, and double check again. Now maybe my version of “slight drag” is a bit off here, but I always hook a dwell meter up afterwards and the past two sets of points have read about 36-38 on the meter, when I should fall more within the 30-34 range. Should I get back in there and regap them? Or is my ocd just getting the best of me?

 

I know the answer! Ditch the points!

Ben

 

http://chevy.oldcarmanualproject.com/shop/1949_53/index.htm

Tune up - 4 or 5 pages starting here -
http://chevy.oldcarmanualproject.com/shop/1949_53/06engine/6_027.HTM
Skip steps at your peril.

http://chevy.oldcarmanualproject.com/shop/1949_53/06engine/6_054.HTM
http://chevy.oldcarmanualproject.com/shop/1949_53/06engine/6_055.HTM

 

Technically speaking, the feeler gauge spec is just to get it close enough so that the engine will start. You're not done yet, then you proceed to check and set the dwell without regard to the resulting point gap. It's the dwell that counts. You don't care what the gap is at this point, the dwell is in spec. Assuming of course, the meter is accurate. Dwell is just a number (degrees) describing how long the points are closed. During this period the coil is getting charged up. Too much or too little dwell time are both less than optimal.

The reason for this method is because as points wear, they build up deposits on one side or the other and are no longer flat, so a flat feeler gauge won't be accurate when using or re-setting used points. In theory, setting the gap with a feeler gauge on a brand new set of points should result in the correct dwell spec.

Does it matter? Maybe, if the dwell is way off it will not provide best smooth power. Usually these days most distributors are getting pretty clapped out by now, once they are all loosey goosey mechanically, the dwell will never come into (or stay in) spec anyhow.

 

Sorry but what you just described doesn't make sense to me. The wire from the ignition should go to the resistor and then a wire from the other side of the resistor to the coil. If you have a wire coming from the starter R terminal, it should go to the hot side of the coil also. It only has power when the starter is cranking and is used to by-pass the resistor during cranking.